Cal. Elec. Code § 2212

The clerk of the superior court of each county, on the basis of the records of the court, shall furnish to the chief elections official of the county, not less frequently than the first day of April and the first day of September of each year, a statement showing the names, addresses, and dates of birth of all persons who have been convicted of felonies since the clerk’s last report. The elections official shall, during the first week of April and the first week of September in each year, cancel the affidavits of registration of those persons who are currently imprisoned or on parole for the conviction of a felony. The clerk shall certify the statement under the seal of the court.